Ehrlichia canis-like agent isolated from a man in Venezuela: antigenic and genetic characterization.

摘要: We report the first isolation and molecular antigenic characterization of a human ehrlichial species in South America. A retrospective study was performed with serum specimens from 6 children clinical signs suggestive ehrlichiosis 43 apparently healthy adults who had close contact dogs exhibiting compatible canine ehrlichiosis. The evaluation by indirect fluorescent-antibody assay Ehrlichia chaffeensis Arkansas, canis Oklahoma, muris antigens. sera two humans were positive for all three Of antigens, samples 1 2 showed highest antibody titers against E. muris, respectively. remaining negative One year later examination blood sample subject revealed morulae morphologically resembling either canis, chaffeensis, or monocytes smear. microorganism, referred to here as Venezuelan ehrlichia (VHE), isolated this person at 4 days after coculturing leukocytes dog macrophage cell line (DH82). organism also mice 10 intraperitoneal inoculation 1. Analysis electron microscopy that isolate ultrastructurally similar muris. When virulence VHE compared those only induced BALB/c days, respectively, inoculation. reisolated peritoneal exudate cells mice. Only chaffeensis- muris-infected developed significant splenomegaly. Western immunoblot analysis reacted major proteins antigen 110, 80, 76, 58, 43, 35, 34 kDa. Human strongly 58-, 54-, 52-, 40-kDa antigen. Anti-E. 26- 24-kDa VHE. In contrast, anti-E. sennetsu rabbit mouse did not react Serum 90, 64, 47 kDa This reaction pattern suggests chaffeensis-infected patients Oklahoma. base sequence 16S rRNA gene most closely related On basis these observations, we suggest is new strain subspecies which may cause asymptomatic persistent infection humans.